This invention relates to electromagnetic projectile launching systems and more particularly to such systems in which initial projectile acceleration occurs within a conventional rifled bore and additional acceleration is provided by electromagnetic forces.
Electromagnetic projectile launchers are known which comprise a pair of conductive rails, a sliding conductive armature between the rails, a source of high current and a switch for commutating this current into the rails and through the armature. Current flow through the rails and armature results in an electromagnetic force on the armature which propels it along the conductive rails. Launchers which utilize a sliding metallic armature have experienced considerable rail damage caused by the sliding armature, particularly where high armature velocities are involved. In these cases, a plasma or arc armature may be more suitable.
The principal disadvantage to the use of a plasma propelling armature has been the damage that occurs to the breech section of the launcher rails during formation of the plasma. Once the plasma is moving, very little, if any, damage occurs to the rails. Because the mass ratio between a projectile and a plasma armature is greater than that between a projectile and a sliding metallic armature, more efficient utilization of available launch package energy is possible with plasma drive. Therefore, the application of plasma driven projectiles in multi-shot systems is appropriate. Such systems include rapid-fire air defense systems and impact fusion reactors.
Several methods have been suggested for initiating a plasma or arc in electromagnetic launcher systems. These procedures are primarily directed toward resolving the problem of creating the plasma armature and minimizing the resulting thermal damage of the launcher rails. Ablation of the rail surfaces is caused by a slow moving or stationary arc and occurs during initial acceleration of the projectile from zero velocity. At higher projectile velocities, the effects of this thermal phenomenon become increasingly insignificant. Therefore a means for imparting initial momentum to the launch package is desired to prolong launcher rail life.
The present invention utilizes conventional rapid-fire powder gun technology to rapidly load and fire projectiles into an electromagnetic launcher bore which continues to accelerate the powder driven projectile to velocities in excess of those attainable with conventional gun powder technology. This electromagnetic launcher system exploits the inherent advantages of both the powder driven and electromagnetic launchers to produce a high repetition rate launcher with superior performance characteristics.